1. Field of the Invention
The present invention relates generally to fall-arrest systems, and more particularly to fall-arrest systems of the type having an anchor that are movable along a rail, e.g., a railway rail.
2. Description of the Prior Art
Fall arrest systems are well known. Such systems typically include an anchor secured to a support structure or other anchor point in the work area, a safety harness or belt worn by the worker, and a flexible cable interconnecting the anchor to the harness or belt. A fall arrest system permits the worker wearing the harness or belt to safely work in areas where he or she is subjected to the risk of falling. The fall arrest system permits the worker to conduct his or her tasks without undue interference, but should the worker fall, the system quickly and safety arrests the fall.
One type of fall arrest system includes an anchor that is movably mounted on a fixed rail, e.g. the rail of a locomotive railway. In this case, the anchor is designed to freely slide or roll along the rail so as to permit the worker to freely move along the rail to, for example, conduct maintenance activities on the railway or on a railway bridge. The anchor can slide along the rail by engaging the rail in such a way as to permit sliding in a longitudinal direction along the rail but at the same time preventing the anchor from separating from the rail or moving in a transverse direction relative to the rail. And, of course, the anchor is securely connected to the worker by means of a safety hook, a cable, and a harness or a belt.
One example of a prior art sliding rail anchor fall arrest system is disclosed in U.S. Pat. No. 5,526,896 to O""Rourke. The O""Rourke anchor includes a pair of formed metal plates each comprising an upper flat portion and a lower curved portion. The flat portions abut together and the curved portions capture and slidably engage the crown of a rail. The flat portion of each plate forms three apertures, the middle of which receives a safety hook, and the outer two of which receive threaded fasteners for holding the abutting flat portions together. One of the outer apertures on each anchor plate is elongated and has a smaller end and a larger end. The flat plates are assembled by loosely attaching the threaded fasteners to the plates; abutting the plate flat portions together so that the larger ends of the elongated holes receive the bolt heads; and longitudinally sliding one plate relative to the other plate so that the bolts then reside in the smaller ends of the elongated apertures. Once the two flat portions are slid together in this fashion, the threaded fasteners can then be tightened to adjust the fit between the anchor and the rail, establishing anything from a loose sliding fit to having the anchor actually clamped to the rail thus permitting no longitudinal movement of the anchor whatsoever.
While the O""Rourke anchor would appear to be generally useful for its intended purpose, it is perceived that it may have some disadvantages. For one thing, the O""Rourke design requires that the workers have the tools and the patience to properly adjust the fit between the anchor and the rail. Also, friction between the flat abutting portions of the plates may hinder the sliding assembly of the plates, especially if there is any corrosion, debris, ice, gravel, etc. therebetween. In addition, it may be difficult to slidably assemble the plates and adjust the tightness of the threaded fasteners when the workers are wearing heavy work gloves or when there is inadequate light. There is also the possibility, however remote, that the fasteners will be loosened excessively, to accommodate the sliding assembly of the plates, thereby potentially increasing the likelihood that the fasteners will become disengaged from the plates.
In further reference to the O""Rourke design, since the elongated apertures must be oriented in the same direction once the plates are abutted, i.e. with both of the larger ends pointed toward a first end of the plates when the plates face one another, a disadvantage of the O""Rourke design is that the two plates are not mirror images of one another, at least with regard to the elongated apertures, thus requiring each plate to be separately manufactured and stocked. In other words, room for improvement remains.
In a preferred embodiment, the present invention includes a fall arrest anchor assembly suitable for operatively engaging a xe2x80x9crailxe2x80x9d and a fall arrest hook. The anchor assembly includes a pair of anchor subassemblies each including an anchor body having a hook engaging portion, a rail engaging portion, an inboard side and an outboard side; an inboard post connected to the inboard side of the hook engaging portion, wherein the inboard post includes a xe2x80x9cheadxe2x80x9d; an inboard post receiving aperture formed in the hook engaging portion, wherein each inboard post receiving aperture receives the inboard post of the other anchor subassembly when the anchor subassemblies are aligned proximate the rail, and laterally moved together; and a latch located on the outboard side of the hook engaging portion, wherein each latch reversibly latches the inboard post head of the other anchor subassembly, whereby the anchor subassemblies are latched together and the anchor assembly is in sliding engagement with the rail.
In a preferred embodiment, the anchor subassemblies are substantially identical to one another.
Preferably each anchor subassembly further includes an outboard post connected to the outboard side of the corresponding hook attachment portion. A preferred latch has first and second ends, wherein the lever first end is pivotally connected to the outboard post and the lever second end forms a slot or notch for engaging the inboard post head of the other anchor subassembly.
In a preferred embodiment the outboard post and the inboard post of each anchor subassembly are axially aligned to one another; and the hook attachment portion can be apertured to permit the associated inboard and outboard posts to connect to one another with the anchor body sandwiched therebetween.
In a preferred embodiment, when the hook is engaged with the hook apertures the latches are locked in engagement with the inboard posts, whereby the anchor subassemblies are locked together.
The present invention also includes an entire sliding rail anchor fall-arrest system including an anchor assembly as described above, a safety hook, a harness or belt that can be worn by a worker, and a flexible cable running from the safety hook to the harness/belt.
The invention is described in greater detail below with reference to the attached Drawings.